This is a family farm, where they grow maize and wheat, as well as raising cattle. The Christensens bought it in 1982 from Mrs Christensen's parents, and it has been in the family since 1760.

They are survivors in an industry that has been squeezed hard. Dairy farming has come under intense pressure around the world in recent years.

Retail giants have demanded the wholesale price of milk fall in many countries, making it more difficult for smaller producers to make a living. Falling sales in the United States in particular has also had an impact.

"One of the challenges we had in the beginning was finding a technology that was able to give us the triangulation or accuracy that was good enough," he says.

When a cow is about to give birth it 'nests' - Gea hopes to improve accuracy enough to spot this

"Until then we have been within several metres. And that is not enough to identify her changes in behaviour."

The system is now accurate to within 30-50cm. UWB also uses relatively little power, giving the tags a shelf life of seven years.

RFID technology is nothing new in farming, but it has traditionally been used to track animals as they move from farm to farm and into the food chain, and to prevent theft.

What makes these tags different is that they are active rather than passive - they transmit signals rather than waiting to be read.

The UWB tags are supplied by RFID and location specialists Zebra Technologies.

"The unique part about our solution as it works with GEA is ... UWB which is ultra-wideband. And all UWB means is it blinks really quick. That's all. It just blinks really fast," says Zebra's Jill Stelfox.

"And if you are talking about a moving cow, even though in theory they move kind of slow, you want the rate of collecting information to happen very quickly."

Analyse this

While a cow will happily wear a collar, pigs have a very different world view.

Pig-headed: Pigs are more particular than cows when it comes to where to wear their tags

"We developed an ear tag, because for sows you can't use anything else, on the neck or leg because they destroy them," says MKW Electronics founder Wolfgang Auer.

"We are the first company to do this with breeding sows."

The plastic housing on the tags is made by MKWE's plastics arm

The Smartbow system also uses RTLS technology to track animal behaviour, and is designed for use with grazing animals including cows. The Austrian company has taken a slightly different approach to GEA.

The sensors operate at a frequency of 2.4ghz, tracking the animals every second. It has a range indoors of 30-100 metres and outside 500 metres. It will tell you where an animal is to within 1.2 metres.

This technology is generally cheaper than UWB - but is less accurate, has a shorter range and is more power-hungry.

The focus for MKW is analytics - and cost. Mr Auer estimates the system should pay for itself in under a year.

In rural areas, a reliable internet connection can be a problem, to MKW's work management software runs on the farmer's own PC rather than in the cloud

"I think accuracy of one metre is enough, what we are doing is in pattern recognition," he says.

"I'm a farmer myself, I have cows at home, and I worked many years at a company that made feeding systems, so I know that the price has to be very low."

The system is accessed through work management software that is accessible from a smartphone, tablet or on a PC.

"It doesn't need an internet connection, the system is running at the farm and not in the cloud. The farmer can also connect from outside via the internet to his server," says Mr Auer.

Starting out

I think the main differentiation is performance versus cost generallyRaghu Das, IDTechEx

"And there is a range of options available. Some do ultra-wideband which gives you high precision in terms of location, but usually, not always, that comes at a higher price point than others which are less accurate.

"So there are a few different technology options."

A reluctance in some parts of the farming industry to adopt new technology will have to be overcome, says Mr Das.

"It is still fairly embryonic with RTLS. I think the main differentiation is performance versus cost generally," according to Mr Das.

"I think it will depend on a case by case basis, because where you have a very dense environment with a lot of cattle, then you may want UWB, or if it is an open field and not very much cattle, then the cheaper system may do."